I live in a place where surf blanks need to be imported, making this hobby very expensive. So i made my own blank mold, and use 3lbs two parts urethane foam inside.
I know this subject has been covered here before but I couldn't find photos or videos showing the actual mold setup and results. So here my constribution to this subject:
Disregard the intergrated fin box system, it did not work well and i cut the tabs off.
The weight of the foam is acceptable but it feels a tiny bit softer then a factory blank and 4lb density would be too heavy i believe.
So far i havn't put any stringer into the blanks, instead i add carbon strips top and bottom. I'm mostly making kitesurf boards since my mold is small.
Now trying to figure out the optimal foam mixture to put inside, if anyone has any good suggestions, i'll gladly absorb the info!
The online information on PU is so spread out that it is hard to figure it all out.
I'm still experimenting with foam colorants, lately i've been adding Titanium dioxide to the foam mix with pretty good results making the foam whiter and hopefully more UV stable.